Combination lock



FIG. 1 is an upper perspective view of the combination lock showing my design.

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is an opposite side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof. 

I claim the ornamental design for a combination lock, as shown and described. 